"German" 870 Wingmaster Identification

[Jaeger]

I hope I have come to the right place for some answers. I just bought a used 870 Wingmaster here in Germany. Now I have some trouble identifying the gun, as in build date. I also have some recoil pad on the end that I don't think is factory and would like to know what the stock end is.

Markings on the receiver are the typical 870 Wingmaster Logo.
Serial Number starting with S and ending with V.
German Proof marks from 71.

Barrel has the Vented Ribs. Marked on left side:
12 Ga for 2 3/4 Shells
imp. Cyl.
German Proof marks from 76
Marked on right side:
B in a Triangle
REP in an Oval

It has an ill-fitting Remington recoil pad attached to the stock. Did the guns of this vintage have a butt plate?
Also, the trigger group does not seem to be original. Feels like cast aluminum, has some nasty casting flash and AlCCO markings (If I read them correct)

[BKinzey]

This link to manufacture dates may help.

http://oldguns.net/sn_php/remdates.htm

Unfortunately dates are for the barrel, so if the barrel has been changed it won't tell you the correct date.

[bigblue]

That gun in Canada was a AP grade 1960 to 1970 manufacturing . They came with a plastic butt plate no rib and the alloy trigger group is correct. Solid smooth guns they retailed for $98.00 dollars Canadian . Not sure about Europe but in Canada they did not come with a vent rib or recoil pad so your barrel may have been changed? and the pad added but the Euro market is different than the North America you see it with Win , browning and and S&W products.

[Jaeger]

Appreciate the input. I do believe that the barrel is not original to the gun. the barrel has a proof mark from 1976 and receiver 1971. I think I will switch to the original butt plate because that recoil pad makes the length of pull uncomfortably long for me. NC ordnance sells a butt plate for a good price, does anyone have some experience with them?